GNU Screen is a terminal multiplexer (window manager). As the name suggests, Screen may be multiplexed between a plurality of physical terminal interactive shell, so we can perform different tasks at each terminal session. All sessions are completely independent of the Screen run the program. Therefore, even if the session closed unexpectedly or disconnected, running in the Screen session or process will continue to run. For example, when using SSH upgrade Ubuntu server, the screen command will continue to run the upgrade process, just in case SSH session is terminated for any reason.
GNU Screen allows us to easily create multiple Screen session and switch between different sessions, copy text between sessions, at any time on or even out of the session and so on. It is one of the important commands for each Linux administrators should learn and use when necessary line tool. In this brief guide, we will see the screen basic usage of commands and examples in Linux.
Install GNU Screen
GNU Screen in most Linux operating system's default repository are available.
To install GNU Screen on Arch Linux, run:
$ sudo pacman -S screensudo pacman -S screenIn Debian, Ubuntu, Linux Mint on:
$ sudo apt-get install screensudo apt-get install screenOn Fedora:
$ sudo dnf install screensudo dnf install screenOn RHEL, CentOS:
$ sudo yum install screensudo yum install screenOn SUSE / openSUSE:
$ sudo zypper install screensudo zypper install screenLet's continue with the screen example command.
A plurality of terminal session management command examples Screen
In the Screen default prefix shortcuts for all commands is Ctrl + a. When you use Screen, you often need to use this shortcut. So, remember this keyboard shortcut.
Creating a new Screen Session
Let's create a new Screen session and connect to it. To do this, type the following command in the terminal:
screenNow, run any program or process in this session, even if you disconnect from this session, process or running program will continue to run.
Released from the Screen session
Out from the screen session, press Ctrl + a and d. You do not need to press the two key combination. First press Ctrl + a and then press d. From the conversation off, you will see something like the following output.
[detached from 29149.pts-0.sk]detached from 29149.pts-0.sk]Here 29149 is the Screen ID, pts-0.sk is the name of a screen session. You can use the Screen ID or session name corresponding to the company, out of the screen and terminates the session.
Create a named session
You can also create a Screen session with any custom name of your choice, instead of the default user name, as shown below.
screen -S ostechnix -S ostechnixThe above command will create a file named xxxxx.ostechnix new Screen session and immediately connect to it. Out from the current session, press Ctrl + aand press d.
When you want to find out what processes are running on which sessions, naming the session would be useful. For example, when the system is disposed in the session LAMP, you can simply be named as follows.
screen -S lampstack -S lampstackCreated out of session
Sometimes, you may want to create a conversation, but do not want to automatically connect to the session. In this case, run the following command to create a file named senthil has been out of the session:
screen -S senthil -d -m -S senthil -d -mIt can be shortened to:
screen -dmS senthil -dmS senthilThe above command will create a named senthil session, but will not connect to it.
Lists the screen session
To list all running sessions (or even on the off), run:
screen -ls -lsSample output:
There are screens on: are screens on: 29700.senthil (Detached)29700.senthil (Detached) 29415.ostechnix (Detached)29415.ostechnix (Detached) 29149.pts-0.sk (Detached)29149.pts-0.sk (Detached)3 Sockets in /run/screens/S-sk. Sockets in /run/screens/S-sk.As you can see, I have three running sessions and all sessions are off.
Even on Screen Session
If you want to connect to the session, for example 29415.ostechnix, simply run:
screen -r 29415.ostechnix -r 29415.ostechnixor:
screen -r ostechnix -r ostechnixOr Screen ID:
screen -r 29415 -r 29415To verify that we connect to the above-mentioned session, just list the open session and check.
screen -ls -lsSample output:
There are screens on: are screens on: 29700.senthil (Detached)29700.senthil (Detached) 29415.ostechnix (Attached)29415.ostechnix (Attached) 29149.pts-0.sk (Detached)29149.pts-0.sk (Detached)3 Sockets in /run/screens/S-sk. Sockets in /run/screens/S-sk.As you can see in the above output, we now connect to the 29415.ostechnix session. To exit the current session, press ctrl + a d.
To create a nested conversation
When we run the screen command, it creates a session for us. However, we can create nested session (a session within the session).
First, create a new session or even open session. Then I will create a file called nested new session.
screen -S nested -S nestedNow, in the session press Ctrl + a and c create another session. Just repeat this operation can create any number of nested Screen session. Each session will be assigned a number. Number from the 0 start.
You can press Ctrl + n to move to the next session, and then press Ctrl + p to move to the previous session.
The following are important session management nested list of keyboard shortcuts.
◈Ctrl + a "
- lists all the sessions ◈
Ctrl + a 0
- Switch to the session number 0◈
Ctrl + a n
- switches to the next session ◈
Ctrl + a p
- a session handover to ◈
Ctrl + a S
- current region is divided horizontally into two regions ◈
Ctrl + a l
- current region is divided vertically into two regions ◈
Ctrl + a Q
- close all sessions except the current session of the ◈
Ctrl + a X
- close the current session ◈
Ctrl + a \
- terminate all sessions and terminate Screen◈
Ctrl + a ?
- display key bindings. To exit, press the Enter Lock Session ####
Screen has an option to lock the session. To do this, press Ctrl + a and x. Enter your password to lock Linux.
Screen used by sk <sk> on ubuntuserver. used by sk <sk> on ubuntuserver.Password::Recording session
You may want to record all the contents Screen session. To do this, simply press Ctrl + a and H can be.
Or, you can use the -L parameters to start a new session to enable logging.
screen -L -LFrom now on, you do all the activities in the session will be recorded and stored in a $HOME directory named screenlog.xfile. Here x is a number.
You can use the cat command or any text viewer to view the contents of the log file.
Screen recording session
Screen session termination
If you no longer need to session, just kill it. To kill called senthil disengagement session:
screen -r senthil -X quit -r senthil -X quitor:
screen -X -S senthil quit -X -S senthil quitor:
screen -X -S 29415 quit -X -S 29415 quitIf there is no open session, you will see the following output:
$ screen -lsscreen -lsNo Sockets found in /run/screens/S-sk. Sockets found in /run/screens/S-sk.For more details, please refer to the man page:
$ man screenman screenThere is also a similar command line utility called Tmux, it performs the same work with GNU Screen. For more information, please refer to the following guidelines.
◈ tmux command examples: managing a plurality of terminal sessionsResources
◈ the GNU Screen Homevia: https://www.ostechnix.com/screen-command-examples-to-manage-multiple-terminal-sessions/
Author: SK topics: lujun9972 Translator: wxy proofread: wxy
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